South 4 Strategy (2)

Now let us talk about riichi judgment in South 4.

There are cases where a riichi that you would normally fire without hesitation
should be held back because of the situation.

Sometimes it is exactly that one riichi stick
that causes your placement to drop.

Example 1

Especially when you enter South 4 in first place,
you should avoid unnecessary riichi and aim simply to end the game.

In Example 1, the flat-game play would be to riichi on the 25p wait and aim for mangan.

But in this score situation,
the absolute correct answer is damaten,
and not only that, to take the easier-to-win 14s wait.

If you are in first place in South 4 and already have a yaku-tenpai, keep it damaten.

If you are so far ahead that there is no realistic danger of being overtaken,
then it can still be fine to press the issue with a yaku-riichi.

As a rough benchmark, that means
a lead large enough that even a direct-hit mangan from second place does not overturn you.

Once you include the riichi stick you are about to put out,
that usually means a gap of at least 18000.

So in practice, those spots are not very common.

Example 2

Even when you are in first place,
there are still situations where you should attack boldly.

For example:

when second place has a strong chance to overtake you
when second place has already riichi'd and the gap is tiny
when, as in Example 2, the opponent already meets their comeback condition whether you riichi or not

If the wait is -,
you can still win in damaten.

But the easier-to-discard cannot be won without riichi.

And can very easily come from Toimen,
who is pushing an open tanyao hand.

Since damaten also has no meaningful improvement path here,
this is exactly the kind of hand and situation where you should riichi.

Putting out the riichi stick does create the risk
that tsumo wins by the players on either side may drop your placement,

but at the moment neither of them is in tenpai yet.

In a spot like this,
do not overthink secondary details.
Just attack.

Example 3

Example 3 is about how to respond to a riichi from the player in last place.

The correct play here is to cut Chun and stay damaten.

No matter what Shimocha tsumos,
you still finish in first place,

so there is no need to go out of your way
to fight them head-on.

After cutting Chun,
if you tsumo , that is fortunate.

If you draw a dangerous tile instead,
just continue cutting Chun and fold quickly.

In a situation where first place is already almost secured,
voluntarily putting a riichi stick on the table is simply foolish.

Finally, a word on staying damaten to wait for a better hand change.

Even in South 4,
there are very few situations where waiting for a hand improvement is truly worth it.

Most of the time,
betting on ippatsu and ura-dora is the more realistic choice.

Example 4
Tsumo Dora West

You are in second place in South 4,
with a tenpai that can improve to Sanshoku in one step.

If the situation is such that:

then immediate riichi is the correct answer.

Especially when the gap is within 3900,
keeping damaten and waiting to switch to is very wasteful.

By common sense alone,
the chance of drawing
is lower than the chance of hitting ippatsu or ura-dora.

If you need a mangan tsumo,
then you stay damaten and wait for the change to .

However, before Sanshoku is completed,
if one of your current winning tiles comes out,
you should obviously take the win.

"Only one kind of improvement, and it must also be the high-side"
is a very demanding condition,

so you should not expect too much from it.